Mast cells (MCs) degranulation have an extremely momentous role in the progresses of immunoreaction, anaphylaxis as well as the variation of the tumor microenvironment (TME). The emergence of the substances due to MCs degranulation will arouse multiple changes of optical characteristics, such as energy transfer, fluorescence and spectra, etc. In this study, we implement the simultaneous spectral unmixing of excitation and emission by adjusting the cube filters and optical path to solely trigger the donor excitation and obtain the acceptor fluorescence emission. In addition, we add another channel to collect the real-time spectra with a portable and mobile spectroscopy equipment. Here, we developed graphene oxide (GO) and reduced GO (rGO)-based fluorescence resonance energy transfer (FRET) biosensors for MCs degranulation to verify the performance of the dual-channel system on an Inverted Fluorescence Microscope. MCs undergo degranulation can rapidly release tryptase, one proteases of the highest concentration in cytozoic pre-formed mediator. The acceptor fluorescence emission and spectra are detected simultaneously in real-time by tryptase-sensitized FRET biosensor on the dual-channel system. Moreover, the dual-channel can be switched by rapid adjusting optical channel during excitation at any moment. Results showed that the MCs degranulation could be monitoring in real-time on the dual-channel optical system. In particular, the minimal changes of the initial degranulation also could be measured with high response rate. Consequently, this dual-channel system may serve as a potential tool for the investigation of protein-protein interaction, single molecule dynamics and the working mechanism of membrane proteins using FRET-related techniques.
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